* Fix junction deviation and jerk settings behavior
Process settings now follow the selected printer's junction deviation
configuration. When machine_max_junction_deviation is enabled,
default_junction_deviation is shown and jerk settings are hidden. When
junction deviation is disabled, jerk settings are restored and
default_junction_deviation is hidden.
Fix a validation issue where junction deviation mismatch warnings could
be reported even when machine_max_junction_deviation was set to 0.
Warnings now apply only when junction deviation is active and point
directly to default_junction_deviation.
Also simplify Motion ability page visibility checks by reusing local
firmware-flavor booleans.
* GUI tweak
- separate Junction Deviation segment
- JD and Jerk stay visible